.snowflake {
  position: fixed;
  /*background-color: #e0e0e0;*/
  /*border-radius: 50%;*/
  pointer-events: none;
  top: -10%;
  z-index: 9999;
  opacity: 0.7;
}

/* 雪花动画 */
@keyframes fall {
  0% {
    transform: translateY(-10%) rotate(0deg);
    opacity: 0.7;
  }
  100% {
    transform: translateY(100vh) rotate(360deg);
    opacity: 0.3;
  }
}
